Piston expander



H. P. PHILLIPS. v

PIS TON EXPANDER March 3, 1942.

Filed May 31, 1940 INVENTOR. BY HAROLD P. PHlLLlPS A RN EYS Patented Mar. 3, 1942 2,274,8Q6 JV PISTON EXPANDER Harold P. Phillips, ,Hastings, Mich., assignor to 7 Hastings Manufacturing Company, Hastings, Mich., a corporation of Michigan Application May 31, 1940, SerialNo. 338,162;

9 Claims. (01. 30942) This invention relates to improvements in piston expanders. l

The main objects of this invention are:

, First, to provide an improved expander for the skirts of internal combustion engine pistons and the like whereby objectional localization of the expansive action on theskirt is prevented.

Second, to provide an expander of the type described which is efiectively locked interiorly of the piston skirt against movement resulting from inertia forces existent at high operating speeds. V

Third, to provide a simple inexpensive expander of the type described in which objectionable wear on the piston skirt is eliminated and which is readily assembled in the piston;

Fourth, to provide an expander for the skirts of pistons of the unsplit type which is easily and quickly installed and at the same time securely retained.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined in the claims.

A structure embodying the features of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a view in vertical section on line 1-4 of Fig. 2 illustrating an internal combustion engine piston with the expander of my invention operatively assembled therewith.

Fig. 2 is a View partially in vertical section on line 2-2 of Fig.1, the view being taken at right angles to that figure.

Fig. 3 is a perspective View illustrating the mounting and thrust distributing element of the expander of the invention.

Fig. 4 is a perspective view illustrating the spring expander element of the invention.

Fig. 5 is a bottom plan view further illustrat-' ing the construction and arrangement of the parts in the embodiment of Figs. 1 to 4.

Fig. 6 is a fragmentary view in section generally similar to that of Fig. 2, illustrating a somewhat modified assembly embodying my invention. p

In the design of expanders for piston skirts adapted to take up for piston wear and collapse, serious trouble has been experienced inthe difficulty of providing locking means successfully effective to lock the expander in the piston skirt so as to resist a tendency to displace the same at high piston speeds. Since the usual piston skirt, particularly in the case of steel pistons, is very flexible, a mere frictional engagement is not always successful to retain an expander in place, hence it is desirable, to provide somepositively actingdevice forthis purpose. L

Moreover, ,a further objection to certain expandersnowon the marketand designed to exert force on the pistonskirt at right angles to the wrist pin so as to render the piston slightly elliptical is the extremely localized action of the expander. This results inoexcessive early wear of the piston skirt in certain small areas or points thereof.

It is therefore the general purpose of the present invention to provide :a piston expander of a simplified nature, which is positively and effectively locked in operative position within the skirt and which, moreover, has means for distributing itsexpansive thrust. .Still further, in thepresent device provision is made for adjusting the force exerted by the expander as may be required in different installations.

Referring to the drawing, the reference nu;- meral l indicates an internal combustion engine piston of an extensively used type- Though particularlydesigned for application to a piston of steel having a thin walled skirt, my invention is not limited in this particular. The piston is provided with conventional .wrist pin bosses 2 in the skirt 3 thereof. In the embodiment of Figs. 1 ,to 5, it will be observed that these bosses are, ribbed 'or'filleted at 4 for strength and rigidity. I

The expander of my invention is of two-part construction including a mounting and force distributing member generallyindicated 5 and illustratedin'Fig. 3, which is in the form of a sheet metal stamping. This memberv has a pair of spaced plate-like vertical side members 6 each provided with a rounded seat .1 adapted to rest on the wrist pin bosses 2 or, alternatively, on the wrist pin immediately adjacent the bosses. Intermediate the parts 6, the member 5 is providedwith angularly arranged arms 8 each ter-/ minating in a segmental thrust applying and distributing surface or pad 9 engageable with theinterior of the piston skirt 3 in the manner clearly illustrated in Fig. 1. The sides of the areas 9 laterally of the arms 8 are bent. double at .10 and, each provided with pairs of notches II for the reception of the expander member or ring l2 illustrated in Fig. 4.

' Theexpanderring I2 is of a highgrade spring steel stock split at I 3 and provided with axial offsets I4 to accommodate the stiffening webs 4 on the wrist pin bosses, it being understood that the forces, distributing thrust members 9 are, -in' operative position, arranged at to either vertical set of notches I I, depending upon the thrust desired or necessary to effect the proper distortion of the piston skirt and in this manner my device provides a range of adjustment of the force exerted thereby.

The sheet metal stirrup or saddle -member.-.5'

does not have any particular spring action or tension in itself, being, as stated, mainly a mounting element performing mainly the functions of mounting. the assembly and, by means of the enlarged pads .or thrust members 9, distributing the radial thrust soas to eliminate objectionable localizing of the thrust and consequent localized wear on the piston skirt. It will be noted that in Fig. 6 1 have indicated an engagement of the plate-like side members 6 of this saddle member with the wrist pin 15 immediately adjacent bosses 2 rather than with the bosses themselves. In this particular, a mere matter of choiceis-involved.

As stated, the outline of expander member I2 is capable of considerable variation so long as it serves effectively as an expanding means and, in addition, restrains axial movement of the assembly in one direction relative to the piston. It may be desired to clear any. projections on the piston skirt other than the ribs 4 and, if desired, could be mademore elliptical or rectangularto this end. In fact, by alterations in design, which will occur to those skilled inthe art, the expander ring may be bent so as to passover the .ends of the wrist pinbosses. I

The foregoing expander assembly has a very effective spring loading action without the'excessive localization of thrust andwear which has commonly characterized hitherto known skirt expanders of the so-called"bu1l ring type. i The tension thereof can be altered either by controlling the design of the expander ring or its relative .positioning with reference to its mounting member .5 therefor. The parts areeffectively locked from movement, which isof considerable importance in the case of a steel ring having substantial flexibility and in which the frictional engagement of the expander is insufficient to prevent shifting.

I have illustrated and described my improvements in an embodiment which is very practical. I have not attempted to illustrate and describe other embodiments or adaptations as it is believed .this disclosure will enable those skilled in the art .to embody or adapt my improvements as may be desired.

Having thus described my invention, what I claim as .new and desire to secure by Letters Patent, is: I

1. An expander assembly for piston skirts, comprising a sheet metal member having integral curved surfaces engageable with the upper half of the connecting rod attaching means of the piston and provided with integral radially directed portions terminating in rounded pads of substantial area concentric with .and engageable with the skirt approximately from said means, and an annular split spring steel ring engageable with said pads to resiliently urge the latter outwardly, said pads having means for adjustably positioning the ring relative thereto and to-prevent axial displacement thereof, and said ring being disposed beneath said connecting rod attaching means and engaging the lower half thereof for coaction with the aforesaid curved surfaces to prevent axial movement of the assembly relative to the piston, said pads distributing the thrust of said ring to prevent localized frictional wearing of the skirt.

.2. An expander assembly for piston skirts, .comprisinga sheet metal member having integral curved surfaces engageable with the upper half of the connecting rod attaching means of the piston and provided with integral radially directed portions terminating in rounded pads of substantial area concentric with and engageable with the skirt approximately 90 from said means, and spring means engageable with said pads to resiliently urge the latter outwardly, said pads having means for adjustably positioning the ring relative thereto and to prevent axial displacement thereof, and said spring means engaging-the lower half of the aforesaidconnecting rod attaching means to prevent axial movement of the assembly relative to the piston, said pads distributing the thrust of said ring to prevent localized frictional wearing of the skirt.

3. An expander assembly for piston skirts, comprising a non-expansible sheet metal member engageable with the piston above the wrist pin bosses of the piston to prevent axial movement of the member, said member being provided with radially directed portions terminating in rounded pads of substantial areaengageable with the skirt intermediate the bosses, and an annular split steel spring engageable with said pads to resiliently urge the latter outwardly, said pads having .means for adjustably positioning the spring relative thereto, said spring engaging the piston .beneath the wrist pin bosses and coacting with said member to prevent movement of the assembly relative to the bosses, said pads distributing .the thrust of said spring to prevent localized. wearing of theskirt. I v

,4. An expander assembly for piston skirts, comprising a non-.expansible member engageable with the .pistonon one side of the wrist pin bossesof the piston to prevent axial movement of the member, said member being provided-with radially .directed portions carrying rounded pads of substantial area engageable with the .skirt intermediate the bosses, and an' annular split steel spring engageable with said pads 'to' resiliently urge the latter outwardly, said' spring engaging theother side of said bosses coacting with 'said member to prevent movement of the assembly relative to the bosses, said pads distributing the thrust of said spring'to prevent localized wearing of the-skirt. y Y

5. An expander assembly forexpanding a]'piston, comprising a sheet metal member-having enlarged thrust members engageable with the skirt at right angles to the wrist pinlbosses therein,,and .an' expansible removable-split expander ring positively engaged with said. member and contactingsaid pads to resiliently urge the same outwardly, said member and ring having portions-engageable with the bosses on opposite axial sides thereof to prevent axial movement of thev assembly relative to the piston,1saidfthrustmom:

bers distributing the thrust of said ring to prevent localized skirt wear.

6. An expander assembly for expanding a piston skirt, comprising a non-expansible saddle member having thrust members engageable with the skirt intermediate the wrist pin bosses therein, and a split expander spring engageable with said thrust members to resiliently urge the same outwardly, said saddle member and spring havof a piston and provided with depending opposed arms terminating in segmental thrust members of substantial area engageable with the skirt of a piston at approximately 90 angle from the axis of the piston pin thereof, said thrust members having reversely bent vertical edges providing inwardly projecting flanges, said flanges having vertically spaced notches therein, and an annular split expander ring selectively engageable with said notches of said thrust members with the expander ring disposed beneath said connecting rod attaching means and engaging the lower surface of the same for coactionwith said saddle member in preventing axial movement of the assembly when arranged within a piston, said expander having reinforcing rib receiving offsets therein,

8. In a piston expander, the combination of a saddle member provided with spaced downwardly facing curved seats engageable with the upper surfaces of the connecting rod attaching means of a piston and provided with depending opposed arms terminating in segmental thrust members of substantial area engageable with the skirt of a piston at approximately 90 angle from the axis of the piston pin thereof, said thrust members having inwardly projecting flanges, said flanges having vertically spaced notches therein, and an annular split expander ring selectively engageable with said notches of said thrust members with the expander ring disposed beneath said connecting rod attaching means and engaging the lower surface of the same for coaction with said saddle member in preventing axial movement of the assembly when arranged within a piston.

9. In a piston expander, the combination of a saddle member provided with spaced downwardly facing curved seats engageable with the upper surface of the connecting rod attaching means of a piston and provided with depending opposed arms terminating in thrust members engageable with theskirt of a piston, said thrust members having notched inwardly projecting flanges,

and an annular split expander ring engageable with said notches of said thrust members with the expander ring disposed beneath said connecting rod attaching means and engaging the lower surface of the same for coaction with said saddle member in preventing axial movement 01 the assembly when arranged within a piston.

HAROLD P. PHILLIPS. 

